Structural insulation sheathing

ABSTRACT

Structural insulation sheathing (SIS), preferably in the form of a panel, comprises a structural member and an insulation member. The structural member and insulation members are in intimate, planar contact with one another, and the SIS structure meets both the structural (that is, AC 269) and insulation (R&gt;2) requirements for the North American residential market. The structural 23 member of the SIS structure is multi-layer laminated paperboard. The insulation member of the SIS is a foamed sheet of a thermoplastic material such as polyisocyanurate.

This application claims the benefit of U.S. Provisional Application No. 60/97,143 filed May 3, 2006.

The residential construction market has structural sheathing (SS) products that offer S no significant insulation value such as oriented strand board (OSB), plywood, fiberboard, and multi-layer pressure-laminated fibrous paperboard. The residential construction market also has insulated sheathing (IS) products that offer only very limited structural properties such as expanded polystyrene (EPS), extruded polystyrene (XPS) and polyisocyanurate foam (PIR). These aforementioned sheathing products are typically in panel form. It would be desirable to have sheathing products that also provide weather resistant properties, therefore reducing the need for synthetic house wraps that are often used in conjunction with structural sheathing and translate to higher installation costs. Producing a sheathing product that combines both insulation and structural properties is desirable. It would be especially desirable if such a sheathing product was also useful for providing a weather resistant barrier.

The invention relates to a sheathing product that combines both insulation and structural properties. In one aspect, this invention relates to structural sheathing. In another aspect, the invention relates to structural insulation sheathing (SIS) and methods for manufacture thereof. Another aspect of the invention relates to a structural insulation sheathing panel comprising at least one facial member and an insulation member. In yet another aspect, the invention relates to a building wall comprising a SIS panel. In still another aspect, the invention relates to a building wall comprising at least two SIS panels that are placed adjacent to each other and in which the joints between the SIS panels are sealed together and the installed panels meet the criteria to be classed as a weather resistant barrier (WRB). Sealing of the two SIS panels may be by way of a weather resistant tape or by any other weather resistant sealing material.

For a foam plastic panel to presently be used as a weather resistant barrier for the North American residential market, it should meet the ICC-ES Acceptance Criteria 71 “Foam Plastic Panels Used as Weather-Resistive Barriers” (AC 71). A more stringent set of criteria is for use of coatings as weather resistant barriers and is set forth in ICC-ES Acceptance Criteria 212, “Water-Resistive Coatings Used as Water-Resistive Barriers Over Exterior Sheathing” (AC 212). Therefore, the AC212 criteria provide helpful guidance for setting standards that would also be useful for describing a “weather resistant barrier” for the sheathing product invention described herein.

ICC-ES Acceptance Criteria 269 (AC 269) “Acceptance Criteria for Racking Shear-Evaluation of Proprietary Sheathing Materials Used as Braced Wall Panels” defines the structural performance of structural sheathing materials for the North American residential market. The North American climate dictates the temperature range for both installation and service. Certain targets for these products include a nominal ½ inch thickness, an insulation rating of R>2, and preferably R>2.5, and the ability to use conventional fastening, for example, adhesives, staples, screws or nails. The conventional fasteners must not detach or pull out under all normal weather conditions. Conventional IS products such as EPS and XPS do not have enough structural strength to meet AC 269 requirements. Even when adhering EPS and XPS insulation sheathing products to known structural sheathing materials to form SIS composite materials using known manufacturing methods, such resulting SIS materials do not have adequate R-value (<2.5) at 7/16 or 9/16 inch thickness for the SIS (that is a thickness that is standard within much of the North American residential market).

Furthermore, in order to effectively attach a conventional SS panel to a building wall, the maximum dimension separating the reinforcing members of its structural component must be less than the diameter of the nail, staple or screw used to structurally secure the product to a stud or other framing element. For plywood or OSB, this is not a problem. However, for a panel comprising a metal mesh facer in combination with a sheet of foamed insulation, the size of the hole through which the nail is fitted must be smaller than the shaft of the nail to insure firm attachment of the panel to the wall. As a practical matter, this requirement eliminates or severely restricts the use of honeycomb and other mesh reinforcements as the structural component of a SIS product because the panel could move once nailed to the wall. Moreover, ideally the head of the screw or nail, or the crown of the staple, is separated from the stud of the building wall to which it is attached only by a wire or strand of the mesh and this, of course, is not possible due to the presence of the insulation component of the SIS product.

One embodiment of the present invention is structural insulation sheathing, preferably in the form of a panel, which comprises a structural member (also known as “facial member”) and an insulation member. The structural and insulation members are in intimate, planar contact with one another, and the SIS structure meets both the structural (that is, AC 269) and insulation (that is, R>2) requirements for the North American residential market. Preferably, the structural member and the insulation member are laminated directly to one another without the use of a separate adhesive composition. Instead, the insulation member and structural member are directly adhered to each other during the foaming process.

The structural member of the SIS structure is a board comprising at least one layer of paper or paperboard. Preferably it comprises a multi-layer laminated paper or paperboard wherein the layers adhere to one another, and on one or both exterior surfaces of the structural member, a protective facer material which will be referred to hereinafter as outer layer of the structural member (OL-SM) and interface layer of the structural member (IL-SM). When employed for sheathing purposes, such multi-layer laminated paper or paperboard is sometimes also referred to in the North American construction trade as “laminated fibrous board sheathing” (LFBS). The OL-SM and IL-SM preferably comprise at least one of the following components: kraft paper, plastic film (for example polyethylene), metallized plastic film, or aluminum foil, and combinations thereof. Within a given SIS, the components of each of these layers may be the same or different. A preferred OL-SM is a plastic film such as polyethylene. It is preferred that the IL-SM have barrier properties to the egress or ingress of gases and it is most preferable that the barrier layer of a multi-layer IL-SM be directly adhered to the foam layer. The thickness of the structural member and insulation member are chosen within the overall thickness required for the product to provide the desired balance of properties based on the sheathing application targeted by the specific grade.

For purposes of meeting the demands of much of the North American residential market, the thickness of the SIS product is desirably from 7/16 to 9/16 inches. With such a thickness for the SIS product, the overall thickness of the structural member is typically between about 0.0625-0.250 inches (about 1.58-4.8 millimeters (mm)), more preferably between about 0.075-0.15 inches (about 1.9-3.81 mm).

The insulation member of the invention comprises foamed compositions that have been formed by dispensing as liquids, sprays or froths of a foamable composition onto the surface of the structural member. Such compositions preferably comprise rigid or semi-rigid polyurethane foams or rigid polyisocyanurate foams. The thickness of the insulation member can be anything sufficient to meet the insulation requirements of the application for which it will be used (for example, typical insulation thicknesses that are common in the marketplace and that would be useful within the present invention include 0.25 inches, 1.0, 2.0 or more inches). Preferably, for purposes of meeting the current demands of the North American residential market, the thickness of the insulation member should be a complement of the thickness of the structural member thickness such that the overall thickness of the SIS product is within the range of about 7/16 and 9/16 inches.

In still another embodiment the invention is a building wall comprising a SIS product in which the SIS product, typically in panel form, comprises a structural member and an insulation member that are in intimate, planar contact with one another. The SIS structure meets both the structural (that is, AC 269) and insulation (that is, R>2.5, preferably R>2.7 more preferably R>2.8) requirements for the North American residential market.

In still another embodiment the invention is a building wall comprising a SIS product in which the SIS product, typically in panel form, comprises a structural member and an insulation member that are in intimate, planar contact with one another and with adjoining panels taped to provide a wall that meets the requirements for a weather resistant barrier. The installed SIS structure meets both the structural (that is, AC 269) and insulation (that is, R>2.5, preferably R>2.7 more preferably R>2.8) requirements for the North American residential market.

In another embodiment, the invention is a process for making a SIS panel comprising the steps of:

-   -   a) feeding a sheet of structural member to a continuous foaming         line;     -   b) dispensing liquids, sprays or froths of a foamable         composition onto the surface of the structural member; and     -   c) allowing the foamable composition to expand and cure.         Preferably, a separate layer [that is OL-IM] is fed onto the         surface of the foamable composition that is opposite that of the         surface of the structural member.

In another embodiment, the invention is a process for making a SIS panel comprising the steps of:

-   -   a) feeding a sheet of structural member to a continuous         lamination line;     -   b) dispensing an adhesive to the surface of one or both of the         structural and the insulation member;     -   c) contacting the structural member to the insulation member         and;     -   d) optionally, passing the combined structure through a nip to         adhesively bond the structural and insulation members of the SIS         panel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of a SIS composite or structure of this invention attached to a stud of a building wall.

FIG. 2 is a photomicrograph of Thermo-ply™ Red, 4 ply laminated board structural member, a preferred structural member material. The four layers of fibrous board, the glue layers and the plastic film exterior facers are noted.

FIG. 3 graphically reports the insulation value R versus the racking strength of the inventive sheathing panel and several commercially available structural sheathing products.

FIG. 4 reports small scale racking test loads as a function of deflections for various sheathing products including the multi-layer laminated board structural members and SIS products of the present invention.

FIG. 5 is a photograph of two SIS panels joined together and attached to typical wall framing with joints sealed with weather resistant tape.

Referring to FIG. 1, one embodiment of the invention is composite panel 10 comprising structural member 11 in intimate planar contact with foam insulation sheet 12. Structural member 11 and foam insulation member 12 may be joined to one another in any conventional manner, but preferably are joined without the use of a separate adhesive composition. The foam insulation member 12 comprises a foam sheet 15 and an optional outer layer of the insulation member (OL-IM) 14. The optional layer OL-IM 14 is typically very thin and made of inexpensive material (for example, fiber, paper, plastic, a composite of two or more of these materials, or, optionally, a reflective material such as a metallized plastic film or aluminum foil, and any combinations thereof).

The composite panel 10 is fastened to stud 13 using conventional fasteners (not shown), for example, nails, screws, staples, adhesives, and similar. While the orientation of the composite to the stud as shown in FIG. 1 (that is, structural member 11 in contact with stud 13), is the preferred orientation to maximize racking strength, in a less preferred embodiment the orientation is reversed (that is, insulation sheet 12 is in contact with stud 13). Optionally, the planar face of foam insulation member 12 opposite the planar face in intimate contact with structural member 11 can be covered or in intimate contact with a nonstructural facer sheet 14. “Planar surface” is used in distinction to “edge surface”. If rectangular in shape or configuration, a panel will comprise two opposing planar surfaces joined by four edge surfaces (two opposing pairs of edge surfaces, each pair intersecting the other pair at right angles). The panels can be of any size and shape and as such, so can the planar and edge surfaces, for example, thin or thick, polygonal or circular, flat or wavy, etc. In light of the disclosure herein, those of skill in the art may appreciate that one configuration for a structural member could consist of an insulation member having structural members located on both sides of the insulation member.

Structural member 11 is further illustrated in FIG. 2. In FIG. 2 a photomicrograph of Thermo-ply™ Red is one example of a multi-layer laminated board structural member. This structural member comprises four layers of paperboard 21 in intimate contact with layers of adhesive 22. Layers 23 (that is OL-SM) and 24 (that is IL-SM) are in adhesive contact with the core layers 21 (CPL-SM) of the structural member.

Because the overall thickness of the SIS structure for use in the majority of the North American building construction market ideally is between about 7/16 and about 9/16 inch, the structural member is manufactured as thin as practical to allow for the use of a sheet of insulation of maximum thickness. The overall thickness of the structural member is typically between about 0.0625 and about 0.250 inches, preferably between about 0.0625 and about 0.15 inches.

The structural member comprises at least one layer of fibrous paper or paperboard. The structural member preferably comprises a multi-layer laminated fibrous board consisting of multiple layers of paperboard core adhered to one another with an adhesive and a non-structural facer material. The structural member may optionally comprise a layer of plastic film such as, for example, polyethylene film. The weight of the combined layers of the structural member is typically from about 180 to 600 pounds per thousand square feet, more preferably, from 250 to 500 pounds per thousand square feet.

By the term “paper”, as it is used herein, it is meant to include all semi-synthetic cellulosic products in all forms of paper and paperboard-like materials. Particularly useful paperboard materials include kraft paper, recycled paperboard, and kraft liner board, which materials are made typically from recycled paper fiber or wood by digestion with a mixture of caustic soda, sodium sulfate, sodium carbonate, and sodium sulfide. These materials may additionally contain conventional paper adjutants such as, for example, strength increasing agents, sizing agents such as, for example, paste rosin, liquid rosin, dispersed rosin, alkyl ketene dimer, alkenyl succinic anhydride, styrene maleic anhydride, wax emulsions, and latex polymer emulsions, preservatives, fillers, clays, kaolin, talc, barium sulfate, calcium carbonate, and similar. For use in the North American residential market, the paperboard may vary in thickness over wide limits from about 0.003 inch to about 0.2 inch. It is also preferred that the paper-board core material be specially treated to be water and weather resistant.

Preferably, a water-resistant paperboard is used in the core layers of the structural member. Water-resistant paperboards typically comprise well-known material conventionally used to manufacture laminated products such as relatively inexpensive, generally stiff, paper product made by a process similar to that for manufacturing paperboard. The paperboard may be made water resistant by the application thereto of a material such as, for example, starch, gelatin, casein, gum, oil, wax, a silicate, a resin, a water soluble polymer, or the like, as well as mixtures thereof. The weight of the water-resistant paperboard may vary over wide limits from about 26 to about 150 pounds per thousand square feet. Preferably, the water-resistant paperboard has a weight of about 75 to about 100 pounds per thousand square feet.

Useful adhesives for bonding multiple paperboard layers include, but are not necessarily limited to, water-based materials such as latex emulsions and dispersions, soluble silicates, phosphate cements, animal-based glues, starch cellulosics, mucilages, and similar, and synthetic materials such as silicates, urethanes, acrylics, polychloroprenes, etc. The adhesive layers alternatively may comprise hydrocarbon resins, rubber latex compounds, elastomer-solvent cements, thermoplastic resins, thermosetting resins, and similar. A water resistant adhesive is preferred. The individual thicknesses of adhesive layers may vary over wide limits from about 0.001 inch to about 0.01 inch, and the adhesive layers may be the same or different.

Examples of materials useful in the OL-SM, IL-SM, and OL-IM layers include kraft paper, plastic film (for example polyethylene), metallized plastic film, aluminum foil, other known facers in the art, and any combinations thereof. The plastic film according to the present invention may comprise polymers including, but not necessarily limited to, polyethylene terephthalate, low, medium, or high density polyethylene, polypropylene, polybutenes, polyisoprene, copolymers of ethylene and/or propylene with one or more copolymerizable monomers such as, for example, styrene, vinyl acetate, acrylic acid, methacrylic acid, methyl methacrylate, butadiene, isoprene, and similar, as well as blends and copolymers of these materials. The first and second layers of polyolefin may be the same or different. The weight of the first and second polyolefin layers may vary over wide limits from about 2 to about 20 pounds per thousand square feet. The weights of the first and second polyolefin layers may be the same or different. It is preferred that the interface layer of the structural member (IL-SM) (that is the layer that is proximate to the insulating member) provide some barrier to egress of the cell gas (blowing agent) of the insulating member. Preferably, the IL-SM should have properties which make it receptive to any inherent adhesive properties of the foamable composition so as to facilitate adhesion of the insulation foam to the structural member during the foaming process.

Examples of suitable structural members include, but are not limited to, Thermo-ply™ Sheathing (Covalence Coated Products) and Thermo-Sheath™ Sheathing products (National Shelter Products). These exemplary products are available in thicknesses ranging from 0.073 inches to 0.137 inches, but other thicknesses outside this range are possible. The surface of the structural member that abuts or is in contact with the construction stud or other frame or reinforcing member (that is the OL-SM) preferably has a rough matt or textured finish to promote attachment of one to the other. The opposite planar surface of the structural member (that is IL-SM) is also preferably a barrier layer to provide some barrier to egress of the cell gas (for example blowing agent) of the insulating member and to allow adhesion of the foamable composition to the structural member. The structural member may contain one or more additives such as pigment, anti-oxidant, flame retardants, processing aids, slow release adhesives (these promote adhesion to the construction stud after nailing or other mechanical fastening of one to the other) and similar.

The insulation sheet or component of the SIS composite comprises foamable materials wherein the foamable compositions are dispensed as liquids, sprays or froths onto the structural member to form a foam on such structural member. These materials are preferably rigid or semi-rigid polyurethane foams, or rigid polyisocyanurate foams. Such preferred foamable compositions are liquids, sprays, or froths at typical processing temperatures and have sufficient adhesive properties to help facilitate adhesion of the foam to the structural members such that the two can be continuously laminated together during the foaming process. Such insulation sheet should also provide insulative properties sufficient for the inventive article of nominal ½ inch thickness to have greater than about (>) 2.5, more preferably >2.7 still more preferably >2.8 rating insulation (R).

The insulation foams are made by conventional techniques and may include typical additives used in insulating foam manufacture, including nucleating additives, infrared absorbers, for example carbon black or graphite, fire retardants, anti-oxidants and similar. The insulating member can also include a filler or insert, such as fiberglass or mesh (see, for example, U.S. Pat. No. 6,030,559). Useful ranges for foam density and cell size are those known in the art for insulation foam. Useful foamable compositions comprise those known in the art such as, for example, those disclosed in U.S. Pat. No. 5,789,458. The preferred thickness of the insulation foams for the North American residential market are such that when joined to the structural member, the total thickness of the composite SIS is between about 7/16 and about 9/16 inch. Those of skill in the art will appreciate that thicknesses outside of this range may be useful for applications outside of the present needs of the North American residential market. For example, it is expected that preferred thickness in some regions may trend towards greater thickness, such as ⅝ inch to 1 inch thick.

The SIS structure can be constructed by any one of a number of different methods. In one embodiment the insulation foam is adhered to the structural member using adhesives applied to one or both of the separate members, followed by bringing the two members together and allowing the adhesive to cure. In a preferred embodiment, on-line PIR liquid foaming is employed directly onto the structural member. The latter promotes good adhesion of the insulation foam to the structural member without the use of separate adhesive compositions and/or an additional lamination step. In this preferred embodiment, desirable insulation values for the SIS structure are achieved via this in situ lamination process. The adhesion of the structural member to the insulation layer may be enhanced by corona treatment of the structural member. In light of the disclosure herein, those of skill in the art will appreciate that other surface treatments of either the structural member or insulation layer can also promote adhesion between the two layers.

The SIS composite structure can be of any size and shape, and conventional sheathing sizes are typically preferred (for example, 4′×8′, 9′ and 10′ length boards). Known adhesives or standard nailing (or staple or screw) patterns are used to attach the SIS composite structure to the wall studs.

The structural member provides the required strength yet is thin enough to allow for sufficient insulting foam. The structural member enables on-line PIR foaming on a continuous line lamination process. As noted above, the PIR foam and structural member are self-bonding, and the addition of the PIR foam to the thin structural member results in a composite structure that achieves a racking performance and insulation value superior to that of the individual components (structural member and PIR foam) alone as shown in FIG. 3.

EXAMPLES Process A for Producing Structural Member/PIR Foam Laminates

A fabrication box (36×35× 9/16 inches) was used as a container to produce restrained-rise foams laminated directly to multi-layer laminated board structural members described above. The structural member was placed exterior-side down in the box, a box pour of polyisocyanurate (PIR) foam precursor was made, a trilaminate facer consisting of kraft paper, a layer of aluminum foil, and a layer of polyethylene terephthalate (PET) film is placed on top of the pour and the box closed providing a restrained rise reaction producing a 9/16 inch thick SIS composite.

The PIR formulation (total of 323.39 g) consisted essentially of Component A (total of 190.89 g), Component B (total of 128 g), and Component C (total of 4.50 g). Component A consisted essentially of PAPI 20 PMDI (poly(diphenylmethane diisocyanate), 181.80 g) available from The Dow Chemical Company (TDCC) and an 80/20 blend of cyclo-pentane and iso-pentane (9.09 g). Component B consisted essentially of Terate 3512 (100 g) available from Invista Corp., an 80/20 blend of cyclo-pentane and iso-pentane (13.20 g), Vorasurf 504 surfactant (2.50 g) available from TDCC, RB 7940 catalyst (11.80 g) available from Albemarle, and water (0.50 g). Component C consisted essentially of Pelcat 9887B surfactant (4.50 g) available from Pelron.

The PIR prototype process consisted of the following conditions and steps:

-   1) All components at room temperature. -   2) Mix A & B for 10 seconds. -   3) Add C and mix for 3 seconds. -   4) Pour into heated mold (that is “fabrication box”) (set at 140 F     for 1 hour to condition) -   5) Close mold. -   6) Maintain mold at 140 F for 1 hour. -   7) Remove from mold

Process B for Producing Structural Member/PIR Foam Laminates

A restrained rise process, as taught in U.S. Pat. No. 4,572,865, was used in which the structural member is fed in sheet form with polyisocyanurate applied between the sheet fed structural member and the OL-IM. The SIS panels produced for Examples 8-10 were produced at 2 inch thickness and skived to the thickness noted in Table 1 before testing. The 2 inch thick sample could not be tested for racking strength because fastening the specimen to the test apparatus was not feasible within the protocol of the test procedure at the time of testing.

For each of the examples, the testing procedures for Tensile Strength (Yield) and Tensile Modulus (Tangent) were as described in ASTM D 638. The testing procedures for Thermal Resistance were as described in ASTM C 518-02e1. The “Small Scale Racking Test” procedure is described in Racking Strength of Paperboard Based Sheathing Materials, Wu Bi, Master of Science, Miami University, Paper Science and Engineering, 2004. The described nailing pattern was followed.

Process C for Producing Structural Member/PIR Foam Laminates

A free rise process makes the PIR insulation member as taught in U.S. Pat. No. 5,789,458 and U.S. Pat. No. 5,837,743. After 24 to 48 hours, the insulation member is sufficiently cured and dimensionally stable to laminate to the structural member. Then a neoprene adhesive, or one of several other classes of adhesives, is applied to one or both members and the two members are brought into planar contact, typically with the assistance of a nip roller.

TABLE 1 Description of Samples with Test Results Structural 16″ Rack 16″ Rack Total Member Corrected R- Load @ 0.3″ Load @ 0.6″ Thickness Thickness Value to Defl. Defl. Ex. Sample Description† (inches) (inches) R-Value†† 9/16″ (lbs.) (lbs)  1** 7/16″ Celotex Fiber Board 0.438 N/A 1.3* — 533 873  2** ¼″ OSB 0.250 N/A 0.4* — 832 1236  3** 7/16″ OSB 0.438 N/A 0.7* — 1087 1778  4** Thermo-ply ™ Red 0.113 0.113 0.22 — 901 998  5 Thermo-ply ™ Red Composite 0.647 0.113 3.71 3.23 869 1129  6 Thermo-ply ™ Blue Composite 0.609 0.137 3.31 3.06 759 1269  7 Thermo-ply ™ Green Composite 0.579 0.078 3.44 3.34 839 892  8 Thermo-ply ™ Red Composite 2.010 0.113 11.86 3.32 ++ ++ Production  9 Thermo-ply ™ Red Composite 0.552 0.113 2.93 2.98 801 1039 Production 10 Thermo-ply ™ Red Composite 0.490 0.113 2.51 2.88 668 928 Production *Published data provided by manufacturer **Not examples of the invention † The Thermo-ply ™ materials are produced by Covalance Building Products, Constantine Michigan. The Celotex fiber board is Sturdy-Brace produced by Knight Celotex Corp.. OSB is oriented strand board and is produced by several manufacturers including Weyerhaeuser and Georgia Pacific. ††R-values were measured at 15 days after insulating foam formation ++ As noted above, the 16″ racking test could not be performed on the 2″ Production Composite sample due to the inability to fasten this specimen in the test apparatus.

The insulating foam and the SIS panel of Examples 5-7 were produced by the method of Process A as per the description above. The insulating foam and the SIS panel of Examples 8-10 were made by Process B described above, Racking Stiffness was determined from the Load vs. Deflection curves by the load at deflections of 0.3 in. and 0.6 in. Exemplary Load vs Deflection curves from the 16 inch racking test are shown in FIG. 4 below.

The Comparative Examples of Table 1 (that is Examples 1-4) all pass the Racking test Section 4.1 of AC 269 (ASTM E72) when the manufacturer's installation instructions are followed. Examples 5-7, at both 0.3 in and 0.6 in deflection tolerate higher loads than does Comparative Example 1. Examples 5 and 7 tolerate loads comparable to those tolerated by Comparative Example 4.

Additional boards made by Process B above, shown as Examples 15 and 16 in Table 2, are selected for testing in the full scale racking test described in ICC-ES Acceptance Criteria 269 (AC 269) “Acceptance Criteria for Racking Shear-Evaluation of Proprietary Sheathing Materials Used as Braced Wall Panels”. The actual procedure used for the testing, whose results are shown in Table 2, is a modification of ASTM E-72 and is referred to as “unrestrained racking” as the testing does not utilize the hold-down rod specified in the test method. Examples 11-14 are comparative examples using existing structural sheathing products and were tested also using the same modified procedure. The fastening pattern for fastening the sheathing product to the racking frame is specified as (x/y/z) where x, y or z is the spacing in inches between fasteners on respectively the top and bottom edges (x), the sides (y) and the interior framing members (z). For all but Example 12, the fastening pattern is (3/3/6). For Example 12, the fastening pattern is (6/6/12). The fastening pattern for the comparative Examples 11-13 is chosen to comply with the manufacturer's recommendations. Comparative Example 14 is equivalent to Comparative Example 13 except that it uses the same fastening system used for the Examples 15 and 16.

TABLE 2 Structural Net Example Total Facer Deflection Ultimate No Sample Description Fastening Thickness Thickness @ 1200 lbs Load 11 7/16″ Celotex Fiber 4 d roofing 0.438 N/A 0.138 3500 Board nails 12 7/16″ Oriented 8 d common 0.438 N/A 0.065 5000 strand board nails 13 Thermo-ply Red 1 × 1.25 in 0.113 0.113 0.140 2360 staples 14 Thermo-ply Red 4 d with 0.113 0.113 0.157 2200 0.113 in shank 15 Thermo-ply ™ Red 4 d with 0.613 0.113 0.191 2500 Composite 0.113 in Production shank 16 Thermo-ply ™ Blue 4 d with 0.135 0.159 4900 Composite 0.113 in Production shank The Comparative Examples of Table 2 (that is Examples 11-14) are commercial structural sheathing products and pass the Racking test Section 4.1 of AC 269 using the manufacturer's installation instructions. Examples 15 and 16 give comparable net deflection and ultimate load when tested according to section 4.1 of AC 269 when fastened as described.

If the SIS panel has a thickness of 0.5625 inches ( 9/16 inch) and if the structural member is without insulation value, then (according to the equation below) the insulating member must have an R-value of at least 4.4 R/inch for the fun panel to have the desired R-value of >2. The insulating member must have an R-value of at least 5.6 R/inch for panel of 0.5625 inch thickness to have the preferred R-value of >2.5. The following expression describes the parameters dictating the R/inch requirements of the insulating layer:

${R\text{/}{inch}_{foam}} = \frac{{R\text{/}{inch}_{Panel} \times t_{Panel}} - {R\text{/}{inch}_{Facer} \times t_{Facer}}}{t_{Foam}}$

The parameter t refers to the thickness of a component of the panel and R.inch refers to the thermal resistance as previously defined. The subscripts refer to the structural member (“Facer”), the insulating member (“Foam”) or the complete panel comprising both components (“Panel”).

Table 3 compares the relative insulation performance of composite SIS panels made by Process B and Process C with the final panel thickness as shown in Table 3. R-values were measured and normalized (using the above equation) to a nominal 9/16 ″SIS panel thickness. Each example had a 0.113 inch structural member with varying insulation member thicknesses. The insulation performance of the insulation members made by the two processes are almost equivalent with Process C appearing to have slightly better insulation performance based on the Normalized R-Value.

TABLE 3 Normalized Example Nominal Total Structural Facer R-value to No Process Thickness Thickness Thickness R-Value 9/16″ 17 B 2″ 2.236 0.113 12.8 2.9 18 B 1″ 1.220 0.113 6.8 2.8 19 C 2″ 2.002 0.113 12.4 3.0 20 C 1″ 1.030 0.113 6.2 3.1 21 C 9/16″ 0.551 0.113 3.2 3.2

In a preferred process for making the inventive SIS panel, a continuous lamination PIR process is believed to be advantaged over using a separate step to laminate the insulating foam layer on the structural member as the overall number of process steps and consequent handling are reduced.

If additional insulation were required to meet increased energy codes requirements for wall insulation, then a product using the same structural member with additional foam thickness could be produced as is shown in Example 8. The technology is identical to that described for the ½ inch nominal product.

Prophetic Full Scale Production Examples

I) A sheet of Thermo-ply™ Red is fed to the full scale process, Process B, to produce SIS product foamed to nominal ½ inch and is tested according to Section 4.1 of AC 269 (ASTM E72) using two different nailing patterns with the results shown as Examples 22 and 23 in Table 4.

II) A sheet of Thermo-ply™ Blue is fed to the full scale process, Process B, to produce SIS product foamed to nominal ½ inch (Example 24) and is tested according to Section 4.1 of AC 269 (ASTM E72) and nailed as indicated with the results shown in Table 4.

TABLE 4 AC 269 Example P(ult)/8/3 P(.2)/8 Allow. Method 4, No Product Fastener and spacing P (0.2″) P(ult) plf plf plf plf 22 Thermo-ply ™ Red Composite 0.113 4 d nail @ 3/2/6 1530 3880 160 190 160 150 Production 23 Thermo-ply ™ Red Composite 0.120 5 d roof nail @ 3/2/6 1477 3810 160 185 160 150 Production 24 Thermo-ply ™ Blue Composite 0.113 4 d nail @ 3/3/6 1880 3970 165 235 165 150 Production

III. A sheet of Thermno-ply™ Red is fed to the full scale process, Process B, to produce SIS product foamed to nominal 1 inch and tested for R-value by ASTM C518. The R-value is 6.8.

IV. A sheet of Thermo-ply™ Red is fed to the full scale process, Process B to produce SIS product foamed to nominal 2 inches and tested for R-value by ASTM C-518. The R-value is 12.8.

SIS panels made by Process B, similar to those described as Examples 21 and 22, were nailed to a 8 ft×8 ft frame composed of conventional wood framing (Examples 25 and 26 respectively). The joints were sealed using WeatherMate™ Construction Tape (The Dow Chemical Company) according to the manufacturer's instructions. The frames are tested similar to AC 212. The assemblies passed this proposed testing criteria which is as stringent as other WRB criteria.

In one embodiment, the structural insulated sheathing is manufactured in a continuous line lamination process using either a restrained rise process as taught in U.S. Pat. No. 4,572,865 with structural member fed in sheet form with polyisocyanurate formulation applied directly to the structural member.

In another embodiment a free-rise process as taught in U.S. Pat. No. 5,789,458 is used in which the structural member is fed in sheet form with polyisocyanurate applied between the sheet fed structural and the OL-IM. In both applications the rigid foam is applied at a density of 1.5-6 pounds per cubic foot and may be manufactured with or without glass fiber reinforcement and with or without reinforcing mesh, for example as described in U.S. Pat. No. 6,030,559 or U.S. Patent Application 20040052035. The OL-IM may be composed of a tri-laminate facer (a 3-ply facer system comprising kraft paper, polyethylene terephthalate and aluminum foil), foil, or kraft paper that may or may not be impregnated with asphalt. The IL-SM may be treated with a chemical or corona process to improve bonding of the structural member to the foamed rigid insulation. The panels manufactured by this process, and having a thickness of greater than or equal to 7/16 inch thickness would be expected to pass Section 4.1 of AC 269 (ASTM E72).

In another embodiment, SIS panels may be manufactured in a glue line lamination process. Here, adhesive is applied to one or both members by spraying, roll coating, or automated hot-melt adhesive applicators. Following the adhesive application, the members are brought together in planar contact with the assistance of a nip roll or a vacuum press with platen is employed to bond the structural members to the insulation layer.

Although the invention has been described in considerable detail, this detail is for the purpose of illustration. Many variations and modifications can be made on the invention as described above without departing from the spirit and scope of the invention as described in the appended claims. All U.S. patents, patent applications, and any other references cited above are incorporated herein by reference. 

1. Structural insulation sheathing (SIS) comprising a structural member and an insulation member in intimate, planar contact with one another, the SIS comprising (i) a structural member comprising at least one layer of water resistant paperboard; and (ii) a foamed insulation member comprising a foam that has been formed from a foamable composition that is dispensed as a liquid, spray or froth onto the structural member to form a foam on such structural member.
 2. The SIS structure of claim 1, wherein the structural member comprises a plurality of superposed water resistant paperboard layers, said layers being adhered together by layers of an adhesive positioned intermediate and contacting adjacent said layers of water resistant paperboard.
 3. The SIS of claim 1 characterized in that it is capable of tolerating a load in a small scale racking test, without failure, of equal to or greater than 875 pounds at a deflection of 0.6 inches, and having an insulation value, R, equal to or greater than about 2.5.
 4. The SIS of claim 1 in which the combined thickness of the structural member and insulation member in intimate planar contact with one another is between about 7/16 and about 9/16 inch.
 5. The SIS of claim 3 characterized as having an insulation value, R, equal to or greater than about 2.7.
 6. The SIS of claim 3 characterized as having an insulation value, R, equal to or greater than about 2.8.
 7. The SIS of claim 1 characterized in that its properties pass the structural performance criteria for the North American residential market set forth at ICC-ES Acceptance Criteria 269 (AC 269) “Acceptance Criteria for Racking Shear-Evaluation of Proprietary Sheathing Materials Used as Braced Wall Panels”.
 8. The SIS of claim 1 in which the foamed insulation member comprises rigid polyisocyanurate or rigid or semi-rigid polyurethane foam.
 9. The SIS of claim 8 in which the face of the foamed insulation member opposite the face of the foamed insulation member in contact with the structural member is in intimate, planar contact with the outer layer of the insulation member (OL-IM).
 10. The SIS of claim 9 in which the OL-IM comprises at least one of fiber, paper, plastic, and aluminum foil.
 11. The SIS of claim 1 in which the thickness of the structural member is between about 0.0625 and 0.250 inches.
 12. The SIS of claim 1 made by an on-line polyisocyanurate liquid foaming process.
 13. The SIS of any of the preceding claims attached to a building wall.
 14. A building wall comprising at least two SIS of claim 13, wherein the two SIS are placed adjacent to each other and are sealed together with a weather resistant sealing material.
 15. The wall structure of claim 14, wherein the wall structure meets the criteria for a Weather Resistant Barrier.
 16. A process for making a SIS panel comprising the steps of a) feeding a sheet of structural member to a continuous foaming line; b) dispensing liquid, sprays, or froths of a foamable composition onto the surface of the structural member; and c) allowing the foamable composition to expand and cure.
 17. The process of claim 16 comprising the additional step of feeding a separate outer layer onto the surface of the foamable composition such that the outer layer adheres to the foam layer of the insulating member.
 18. The process of claim 17 wherein the outer layer is a barrier material for inhibiting egress of cell gas from the insulating member. 